Field of the Invention
Embodiments of the invention relate generally to information handling systems. More specifically, embodiments of the invention provide an improved method and apparatus for transporting data between an information handling system and peripheral devices.
Description of the Related Art
As the value and use of information continues to increase, individuals and businesses seek additional ways to process and store information. One option available to users is information handling systems. An information handling system generally processes, compiles, stores, and/or communicates information or data for business, personal, or other purposes thereby allowing users to take advantage of the value of the information. Because technology and information handling needs and requirements vary between different users or applications, information handling systems may also vary regarding what information is handled, how the information is handled, how much information is processed, stored, or communicated, and how quickly and efficiently the information may be processed, stored, or communicated.
The variations in information handling systems allow for information handling systems to be general or configured for a specific user or specific use such as financial transaction processing, airline reservations, enterprise data storage, or global communications. In addition, information handling systems may include a variety of hardware and software components that may be configured to process, store, and communicate information and may include one or more computer systems, data storage systems, and networking systems.
Digital displays have become increasingly popular and include flat panel screens and projectors that are used not just with information handling systems, but also with video display systems in both consumer and corporate environments. While many of these displays can accept analog signal input, their optimum resolution is best realized through a digital interface capable of mapping a video image to the native resolution of the panel. As a result, there has been a steady migration away from video graphics array (VGA) and component RGB video analog input to digital interfaces such as digital video interface (DVI). Unlike analog interfaces which are affected by electrical noise and other sources of distortion, DVI's digital protocol uses binary data to control the desired brightness of each pixel in the display. A single DVI link consists of four twisted pairs of wire (red, green, blue, and clock) to transmit 24 bits per pixel, which closely matches that of an analog video signal. However, maximum resolution for a single DVI link at 60 Hz is limited to 2.6 megapixels. A second DVI link can be enabled if greater bandwidth (e.g., for high definition television) is required, but DVI is limited to no more than two links. Another limitation is DVI's lack of inherent support of digital content copy protection. High-Bandwidth Digital Content Protection (HDCP), a form of digital rights management (DRM) developed by Intel Corporation, can be implemented on DVI, but HDCP is supported on a limited number of digital displays, which limits its effectiveness.
High-Definition Multimedia Interface (HDMI) is another digital interface that is currently gaining popularity. HDMI provides a maximum bandwidth of 340 megapixels/second, which is capable of supporting the highest resolution computer monitors currently available. When coupled to an HDMI display, HDCP is automatically supported to provide digital content protection capabilities. Furthermore, HDMI is backwards-compatible with single-link DVI implementations when an adapter cable is used. However, computer, audio/video, and digital display manufacturers share a number of concerns regarding DVI and HDMI. First, they are concerned about future computer display bandwidth requirements, which DVI and HDMI fail to address. Second, they recognize the need to support more comprehensive encryption standards for improved digital content protection. Third, they are aware that several video standards are being implemented in parallel, which confuses consumers and complicates installations. Ideally, they would prefer a single, universal digital interface standard that uses a common, multi-purpose cable regardless of whether it is implemented for computers, audio/video equipment, or both.
These technology and market drivers have led to the development of the DisplayPort video interface by the Video Electronics Standards Association (VESA). DisplayPort is based on the physical (PHY) layer of the 2.5-Gbit/s PCI Express (PCIe) bus to provide bandwidth of up to 10.8 Gbits/s over four channels, commonly referred to as “lanes.” It also delivers an improved copy protection scheme that uses a 128-bit encryption key in concert with the advanced encryption standard (AES) as opposed to the 40-bit key used in HDCP. Furthermore, it adds support for checking the proximity of the transmitting device (e.g., computer system) and video receiver (e.g., flat panel display) to further prevent the unauthorized distribution of digital content. Concurrently, a cable specification is in progress that would allow the PCIe bus to be extended. This extension would allow the external attachment of high-performance peripherals to computer systems, many of which are used in multi-media entertainment systems. However, implementation of these peripherals would require attaching a PCIe cable to the host system, which may not be easily accessible, and would add an additional cable for the user to manage. Ideally, the PCIe bus would be extended to the DisplayPort device to facilitate the attachment of a PCIe peripheral, but no such capability currently exists.